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P Malagoli

Publications and source records attributed to P Malagoli.

5 recordsLinked to original sources
PubMed2005

Dynamics of nitrogen uptake and mobilization in field-grown winter oilseed rape (Brassica napus) from stem extension to harvest. II. An 15N-labelling-based simulation model of N partitioning between vegetative and reproductive tissues.

BACKGROUND AND AIMS: Oilseed rape (Brassica napus) has often been used as a catch crop to deal with the issue of N leaching, but for this to be effective, prediction of the crop's N uptake capability and N partitioning is required. The aim of this work was to build a compartmental model of N dynamics in oilseed rape, based on the kinetic description of N uptake, partitioning and mobilization in each organ. MODEL: In this study, logistic and exponential equations were fitted to the N relations of each compartment, especially the leaf at each node. Data previously obtained from an 15N-labelling field experiment was used to quantify the partitioning of total N content, the allocation of N taken up and subsequent changes in the sink/source status for endogenous N in each tissue throughout the growth cycle. KEY RESULTS AND CONCLUSIONS: This modelling approach provides a unique tool for the quantitative estimation of cycling of endogenous N in relation to changes in N uptake at the whole-plant level. Furthermore, as oilseed rape is known to release large amounts of N to the soil during spring through leaf loss, this model was used to identify potential methods for improving the N harvest index of the crop. Simulations showed that N content or yield could be improved by 15% by optimizing N transfer from vegetative to reproductive tissues and by reducing the residual %N (DW) in abscised leaves.

Biological Transport, Active↗
PubMed2005

Dynamics of nitrogen uptake and mobilization in field-grown winter oilseed rape (Brassica napus) from stem extension to harvest: I. Global N flows between vegetative and reproductive tissues in relation to leaf fall and their residual N.

BACKGROUND AND AIMS: Despite its high capacity to take up nitrate from the soil, winter oilseed rape (Brassica napus) is characterized by a very low N recovery in the reproductive tissues under field conditions. A significant part of the N taken up is lost to the soil in dead leaves during the growth cycle. An accurate description of N dynamics at the whole plant level in each compartment under field conditions should lead to a better understanding of N allocation in B. napus and improvements in the nitrogen harvest index. METHODS: An experiment was conducted in field conditions using sequential weekly 15N labelling to follow N uptake, partitioning and mobilization. Nitrogen labelling (2.5 kg N ha(-1); 10 % excess) was analysed weekly (from stem extension to harvest) to distinguish between uptake of new N (labelled) and mobilized N (unlabelled) in the different plant components. KEY RESULTS AND CONCLUSIONS: N requirements for seed filling were satisfied mainly by N mobilized from vegetative parts (about 73 % of the total N in pods). Determination of the endogenous N flow showed that there was net transfer of N to the pods by leaves (36 %), stem (34 %), inflorescences (22 %) and taproot (8 %). Precise study of N flow from leaves at different nodes revealed the existence of two main groups of leaves in terms of their apparent capacity to mobilize N; 30-60 % and 70-80 % of peak N content occurring during flowering and pod filling, respectively. Moreover, the latter group was found to be the main source of endogenous N from leaves. The mobilization of endogenous N from these leaves was prolonged and concomitant with N accumulation in the pods. A complex pattern of N mobilization from the leaves, to vegetative or reproductive tissues, was revealed. These results will be used to model N partitioning during the growth cycle.

Biological Transport↗
PubMed1994

Treatment of severe alopecia areata with squaric acid dibutylester in pediatric patients.

Topical squaric dibutylester (SADBE) is currently used in Europe to treat alopecia areata in adults. We attempted to determine this drug's effectiveness and convenience in treating children with severe alopecia areata who are psychologically disturbed and resistant to other therapies. Twenty-eight children under 13 years of age who had extensive and long-standing alopecia areata and were not responsive to conventional therapies were sensitized on the head with 2% SADBE in acetone and treated with weekly applications for 12 months. Nine patients (32.1%) achieved complete or cosmetically acceptable regrowth, and another six (21.4%) had significant regrowth. No correlation was found between response and sex, age of onset of illness, extent, duration, or clinical type of disease. In 14 patients followed for a period ranging from 18 months to 8 years SADBE remained efficacious for relapses as well. This study demonstrates that SADBE is a valid and suitable treatment for children, particularly those who are resistant to conventional therapies.

Administration, Cutaneous↗
PubMed1992

Vitiligo is associated with a significant increase in HLA-A30, Cw6 and DQw3 and a decrease in C4AQ0 in northern Italian patients.

HLA polymorphisms of class I (HLA-A, B, C) of class II (HLA-DR, DQ) and of class III (C4A, C4B, BF) were investigated in 93 Northern Italian patients affected with vitiligo and in 388 controls. Vitiligo patients had significant increases in HLA-A30 (corrected p, pc = 0.0144), Cw6 (pc = 0.0189), DQw3 (pc less than 0.0003) and a significant decrease in C4AQ0 (pc = 0.003). Nonfamilial vitiligo is marked by increases in HLA-A30 and DQw3. Extensive vitiligo is marked by increases in HLA-A30 and Cw6. These findings suggest that immunogenetic mechanisms may be responsible for vitiligo and that unique HLA phenotypes may influence the expression of vitiligo in this population.

Adolescent↗